Interpretive Summary: Global food security largely depends on annual grain crops, which need to be replanted every year and make up nearly 70% of human caloric consumption globally. Annual grain crop production; however, often leads to soil erosion and loss of soil water and nutrients, which can lower farm productivity, especially on marginal lands. Perennial crops, which are planted once and regrow every year, generally have advantages over annuals in preventing these losses. Compared to their annual counterparts, perennial plants generally have longer growing seasons and are able to capture and use more of the natural rainfall. Their greater rooting ability reduces erosion risks and maintains 30 percent or higher levels of soil organic matter. Scientists have also documented 35-fold reductions in fertilizer loss under perennial cropping systems. Because they do not need to be replanted every year, perennial crops require fewer passes of farm equipment and lower inputs of fertilizer and pesticides. Past efforts to develop perennial grain crops were hindered by the lack of modern plant breeding technologies; however, new biotechnology tools will allow plant breeders to develop perennial lines and varieties with greater efficiency in the process. Argentina, Australia, China, Sweden, and the United States have already initiated modern programs to develop perennial grain crops. With greater scientific capacity, plant scientists could soon have our first high-yielding perennial grain crops ready for production.

Technical Abstract:
Global food security largely depends on annual grain crops, including cereals, oilseeds, and legumes, which make up nearly 70% of human caloric consumption globally. Annual grain crop production; however, often compromises essential ecosystem services, which can lead to partial or complete loss of productivity, especially on marginal lands. Perennial crops generally have advantages over annuals in maintaining important ecosystem functions. Compared to their annual counterparts, perennial plants generally have longer growing seasons, deeper rooting depths, and intercept, retain, and utilize more of the natural precipitation. Their greater belowground productivity reduces erosion risks and maintains 30 percent or higher levels of soil carbon than those maintained by annual crops. Scientists have also documented 5-fold reductions in water loss and 35-fold reductions in nitrate loss under perennial cropping systems. Because they do not need to be replanted every year, perennial crops require fewer passes of farm equipment and lower inputs of fertilizer and pesticides. Past efforts to develop perennial grain crops were hindered by the lack of modern plant breeding technologies; however, new genetic technologies such as genome-wide selection will allow plant breeders to develop lines and varieties with greater efficiency in the process. Argentina, Australia, China, Sweden, and the United States have already initiated modern programs to develop perennial grain crops. With greater scientific capacity, plant scientists could soon have our first high-yielding perennial grain crops ready for production.